slave cylinder bleeding how to help.. please
 

Not sure why I can't get the clutch pedal to come off the floor.

1. Should pedal be on floor or up while using power bleeder?
2. Do I have to bleed master clutch cylinder and slave separately?

What I'm doing is filling reservoir, hooking up motive power bleeder and pumping up some pressure (15 psi ) with over flow line pinched closed not to lose fluid from reservoir.
Going under car and opening bleeder on slave some air some fluid closing bleeder valve. Check clutch pedal nothing...

Drivers rear is up on a jack stand..with wheel off
Thanks in advance

Bob,

NO! the clutch pedal should not be on the floor! You may need to pull it up and depress it serveral times, but while you a bleeding it the pedal should not fall to the floor. Sometimes while bleeding you can inadvertantly depress the pedal and vacuum air back into the system...

Also, that 7mm bleeder screw is very hard to get to. Make sure you have closed and tightened it properly...

I doubt you have any real problems though, lol, I've seen tons of cars where you'd bleed the slave cylinder just for maintenance purposes and the pedal randomly decided to be stubborn.

Best of luck

btw, where in cape cod are you? I was just in Chatham.

I've always bleed mine at the slave, the old fashioned way.

Hydraulic pressure makes the clutch pedal rise is hydraulic pressure. I suspect you simply don't have enough pressure built up to take up all the "slack" in the system. Try working the pedal by hand four or five times. See if that builds enough residual pressure to make the pedal work.

Just south of the Bourne Bridge

So its a two person job? One to push on clutch pedal and as it's being depressed second person opens bleeder and closes bleeder before pedal is released? This should build pressure up on pedal.

Pushing the pedal by hand I feel just some slight pressure at a inch from bottoming out.. I should have someone hold down the pedal and then open the bleeder releasing any air fluid in the system then closing the bleeder before the pedal is released, repeating this procedure several times?

No, you shouldn't touch the clutch pedal while bleeding. You just need to bleed the crap out of it. The pedal should be all the way up while bleeding and never depress it while bleeding. Once you have air in there, it takes a lot of bleeding to get it out.

Is it possible to un-bolt the slave cylinder from the bell housing and cycle the slave cylinder by hand. I had a 928 with a hydraulic cluth and had a hard time bleeding the air. I got a tip online about disconnecting the slave cylinder and pushing in the rod by hand in and out.

I could instantly hear the air coming out of the master cylinder. After a couple of cycles I bolted it back up and it was perfect. On the 928 the slave cylinder is connected by a rubber hose and made it really easy to use this method.

the slave cylinder is not coming off without removing the transmission on a 911.

Like most of us have said, you'll probably need to pump the pedal a few times to build up pressure, and then just let a lot of fluid run through it. You should be fine.

How much fluid would I need to run through the system to get the air out?

Some conflicting information here...

Can and should all the bleeding be done at the slave?

if you haven't touched the master, then the slave should be fine.

Not really conflicting information. When you bleed the slave, you should not depress the clutch and allow it to come down. For whatever reason that happened, now you probably need to pump it several times, probably reaching and physically pulling it back up. Normally, however, you simply don't touch the pedal when you bleed it.

I wouldn't think it could possibly take more than a liter of fluid.

I've introduced air in my clutch line by running the level too low during bleeding. When that happened the clutch threw itself to the floor and stayed there when I initially pressed it after the bleed. I had to pull it back up by hand. It took just a little less than a liter as you say to get all the air out. I went ahead and used the whole liter anyway just to be sure

I couldn't pump, it would just body slam itself to the floor. Bleeding will take care of the air. Just get the clutch to stand up by hand and bleed. You're right, you definitely don't want to pump the clutch pedal while bleeding. I think we're pretty much in agreement, it's just in the details. :)

Do you guys have the Bentley Service Manual?
Page 301-10

The manual states: 1. bleed until no air in system with power bleeder 2. with air bleed screw open slowly depress clutch pedal fully several times 3. with pedal fully depressed close bleeder screw 4. remove pressure bleeder top of fluid

I've removed the one on my 911 without dropping the motor or trans...

But back to Bob-in-Cape-Cod's issue. Have you tried simply pumping the pedal a few times?

Remember the front of the car needs to be higher than the rear to bleed the slave cylinder - bleeder screw needs to be at the high spot.

Also, if you got lazy like me and just jacked up one side of the car, the reservoir nipple that feeds the clutch master cylinder is now in a spot with very little (if any) brake fluid (if you use the pressure bleeder dry).

I did not learn the above by introspection like one might presume, but instead by doing the wrong thing and suffering the consequences... goes to show, sometimes it's best to walk away before one does silly things. It usually saves time. Now I just need to follow my own advice.

Once I corrected both of these things, mine bled just fine.

Yes Capt.
No pressure building up.. @ 51 I felt my age laying on the concrete for 3 hours last night, looking for answers in the easy chair before I dive under the trany again to get all greasy for the second time. The first hour was to remove the slave, the next hour was cleaning inspection and reinstalling the slave (by the way removing the little bracket that holds the line was a must for me to get a wrench on the fluid line). 3rd hour was tying to get the pedal back.

I have one corner up and used the power bleeder dry.. hence the air in the line.
Will fluid in the power bleeder do the trick or is it a must to get the front of the car up

Let's start at the beginning. What precipitated the need to bleed the line? What did you replace and why?


While I await your response, I suggest you try gravity-bleeding the line. Simply open the bleed screw on the slave, with the clutch pedal up. Just let the fluid flow until the air is out. No pressure devices or assistance needed. When you think the air is out, close the bleed screw, pump the pedal a time or two, and you should be good. It shouldn't take more than ten minutes.

A few helpful tips: Use a length of clear tubing over the bleed screw. You can see the air bubbles, and it keep the mess down. Don't worry about tipping the car. If fluid is coming out the slave, the slave is lower than the reservoir.

Report back. Especially regarding how this problem started.

Two weeks ago Sat. I had some fun at a AutoX event, on one run I went into a spin and put both feet in. I think that's what started the problem... last Sat. running with a group for our monthly run I noticed that my clutch pedal seemed soft at the top 2/3" and my reservoir was lower then normal. Added some fluid (pedal felt better) I put a piece of cardboard under the engine / transmission area; the next morning I checked and had some leaking from the area.
I decided to remove the slave after looking though the inspection opening and seeing the push rod looked wet from fluid. Since I had no problems rebuilding my break calipers 2 years ago I felt that opening up the slave would be worth the effort all of 2 minutes. Cleaned some gunk out of cylinder and around the seal reassembled and reinstalled to test for any leaks. My intention is to replace the slave if loss of fluid appears after getting my pedal back. I guess you can look at this as the practice run on replacing the slave in the near future.
Thanks for your help

http://forums.pelicanparts.com/uploa...1219197147.jpg
http://forums.pelicanparts.com/uploa...1219197175.jpg
http://forums.pelicanparts.com/uploa...1219197215.jpg


More pics from thhe fun run:
http://restlessnative.smugmug.com/gallery/5726544_obzUh#353518348_9TMAx

If you did a dry bleed you likely made the most common mistake of running the fluid too low in the reservoir. The pickup for the clutch circuit is mid height in the reservoir as opposed to the brake circuit which is in the bottom. Once the fluid level gets to midway down in the reservoir, you're introducing air into the clutch line. Use the "wet method" and fill your pressure bleeder with at least a liter of fluid and run it through. If it's still blowing bubbles after that, add another liter and try again. That will fix you up. The car tilting thing makes no sense to me. You don't do that when you bleed the brakes, right? This is no different. Just pump fluid through it until you have no more bubbles and don't let the reservoir go below half full in the process.

Regards,

The slave cylinder is a horizontal unit with the bleeder screw in the front. If the rear of the car is higher, the bleeder screw will not be at the highest point of the cylinder, leaving room for an air bubble towards the rear.

With the calipers, the bleeder screw is at the top of the caliper regardless of orientation (within reason ...)

Bob,

I presume you've confirmed the slave is no longer leaking, and the push-rod is seated in the clutch fork? Have you verified the master, under the toe-board, is also not leaking?

Here's what it looks like:

http://members.rennlist.com/imcarthur/clutch-slave.jpg

Here's what John Walker told me:

"you don't need any fancy equipment. put a short 7mm box end wrench on the bleeder, attach a drain hose aimed at a pan, open bleeder a 1/4 turn, pump the pedal all the way down and slowly back up a few times, wait a few seconds between pumps, stop with the pedal all the way up, go under and close the bleeder and then test the pedal to be sure it feels normal. same way you do a one man brake bleed. i've used suction and pressure bleeders and had limited luck. usually could not get a decent pedal. sometimes you get lucky. just because the fluid comes out with them, doesn't mean it's going to work. not sure why, but the hand pumping always works."

In this post: http://forums.pelicanparts.com/porsche-911-technical-forum/412026-can-you-put-speed-bleeder-clutch.html?highlight=bleed

And he was right. His method worked & the Motive failed.

Ian

Interesting. That's not my experience. I've bled my clutch slave with the Motive many times (in conjunction with brake bleeding before track events) and never had a problem. I had just as much flow as what came out of the calipers. Never had to do any pumping or tilting to get good results.

Regards,

Steve

Yeah, this is starting to sound more like you might have an issue with the slave cylinder if it was leaking to begin with, and now you've just introduced a high pressure flow of fluid to it that might have made a problem worse. It's entirely possible the slave cylinder is sucking air in through wherever it's been leaking.

With fluid under pressure w/ power bleeder no leaks out of the slave, I haven't checked the master.. the leak was coming from the slave before cleaning and reassembling. The push-rod is seated on the fork correctly

I'll run a pint of fluid tonight and post whats going on.
Thanks everyone, it appears everyone has different methods and results based on how much air is in the system. I think I introduced allot of air in the system buy using the motive dry, so I have to look at it like I have multiple pockets of air in the system. I'll do a wet pressure bleed tonight.

All set guys, thanks
I pushed some fluid through the system with the motive power bleeder (filled w/ a quart).
After some blazing saddle action, I closed the bleeder to test the pedal and it firmed up some. The next thing I did was pump the clutch pedal several times with the power bleeder sill attached, then under the car to open the bleeder again to release any other air that I moved around in the system and I did get some out. I did that two more times then the pedal felt pretty good. Reinstalled the line bracket, rubber view cover that exposes the push-rod and clutch fork ear. Disconnected the power bleeder and clamp on the over flow tube.
Put the tire back on and lowered the car for the test drive. All is good.
Kitty littered the garage floor, now if everything stays dry I'm going to be satisfied with my work. Down the road if I have to replace the slave It should go pretty quick now that I have the experience.
Again thanks for your help guys

I am confused. If you open the bleeder valve, then pump the pedal. Soon you release the pedal up, isn't air will be sucked into the system through the opened bleeder valve?

You have to move reseaonably quickly. I had a wrench on it (wedged up because the weight of the wrench closed it). Do the pumping by hand leaning into the car, then quickly close the wrench - fluid is still coming out as you close it from what I remember. The Motive just didn't produce a confident stream of fluid the way it does for brakes from my experience.

My pedal is nice & firm.:)

Ian

as long as the system is under pressure it is impossible to allow air in... same with using a powerbleeder for brakes... you can pump the brakes all you want while bleeding them with a power bleeder becasue air annot come back into the system, it's usefull too when you're trying to replace the entire fluid volume.

Oh I thought you meant doing it the manual way. If you are doing it with the power bleeder, I thought you don't need to pump the pedal anymore?

http://forums.pelicanparts.com/uploa...1221955118.jpg
After doing lots of research this is what I found out, it seems like Beck Arnley makes 5 or 6 rebuild kits for slaves used on German cars etc. and get this Toyota pickup trucks. You can do a Internet search on Beck Arnley slave cylinder rebuild kits to check it out. Our host sells the part under the 928 section 928-116-901-00-OEM Rebuild Kit for Clutch Slave Cylinder, 924/944 All (1977-91), Each
Brand: Genuine Porsche $22.75.
I installed the cup seal that comes w/ this kit in my slave cylinder after my leak came back one week after my cleaning and replacing the part. When I took the old cup seal off it was worn, dry and brittle with some hair-line cracks that was allowing the fluid to pass by. The cylinder and piston were fine no scratches or any ware. Tip: put new seal in hot water to soften up, it will be more pliable to put on the piston.

I had the same thought, looking for rebuild part, when I opened up my old slave. Mine car is an 87 with a G50 tranny but the slave doesn't look the same as yours. Mine has a piston, a big spring, and a rubber o-ring seal; which goes over the piston. What makes the slave leak is the rubber o-ring. If I can find that o-ring, problem solved.
In your pic above, I don't see the piston and that o-ring. And on my slave, I don't have all those parts beside the spiral lock washer.

rnln,
Mine is a 87 G-50> top right is the cup seal that goes on the piston.
http://forums.pelicanparts.com/uploa...1222032417.jpg
http://forums.pelicanparts.com/uploa...1222032446.jpg
This is how my slave looked off the car.

The brass ring holds the small end of the dust boot to the push rod, the large gear looking washer holds the large end of the dust boot against cylinder casting, the little cap is for bleeder. I didn't use any of those parts because mine were in good shape.
The cup seal goes on the piston with the view you see in the picture facing the spring in the cylinder, as fluid comes into the slave from the feed line.. pressure pushes against the cup seal keeping the outer edge of seal tight on cylinder wall. I'm not sure if a O-ring would work. Inner Diameter 16mm OD 24mm 6mm wide. The diameter of the cup seal is tapered wider on the side you see in the picture by about 1mm. Put the spring in cylinder first, piston next with wider tapered end of seal going into cylinder next.

umm... the slave on my car look the same, except for the cup seal on yours. Mines are just the o-ring. It goes on the grove on the piston. It won't expand the way your cup seal works. It just slide against the cylinder wall. It does have a big spring inside the cylinder.
Anyway, how much that kit cost you? I got the new slave for around $100 bucks because I couldn't find the kit or o-ring anywhere.

under 30$ with shipping

928-116-901-00-OEM Rebuild Kit for Clutch Slave Cylinder, 924/944 All (1977-91), Each
Brand: Genuine Porsche $22.75. available from our host

70$ in my pocket > close to 250% return on investment with sustainable responsibility until I run the savings though the injectors; about 500 miles of pleasure... priceless

I know what to do next time. Thanks Bob.

rcaradimos, you get 500 miles from $70 of gas? Pretty darn good ... or you get cheap 93 octane. Love your analysis either way :)

Thanks for the part number - I'll keep it stored away someplace where I won't find it when I need it... even better, I'll add this:

clutch slave cylinder rebuild kit part number g50 hydraulic forgot

And maybe now search will find it for me. Hahahaha - take that, lousy brain - I don't need you anymore!

(I need some coffee this morning - and soon.)

burgermeister
LOL
25mi per gal @ $3.50... 87octane the good stuff, My car is from California and has the retarded spark like me:D burning 87 the car runs better. I think if your timing is advanced by way of a chip you need to use the 91+ I'm happy with the performance on this 187K motor.. no need to mix drinks on the old girl she could puke on me and that wouldn't be fun.